Reconstruction of Ocean Velocities from the Synergy between SST and SSH from SARM Measurements
Isern-Fonatnet, Jordi1; Martin-Puig, Cristina2; Gonzalez-Haro, Cristina1
1Institut Català de Ciències del Clima, SPAIN; 2isardSAT, SPAIN
Along-track altimetric measurements of Sea Surface Heights (SSH) are very well suited to quantify across-track currents. However, the spatial resolution of derived 2D velocities is restricted to scales above 100-150 km and the limited number of altimeters can lead to errors in the location of currents. On the contrary, infrared measurements of Sea Surface Temperature (SST) are well suited to locate flow patterns but it is difficult to extract quantitative estimations of ocean currents.
To overcome the previous constrains we have developed a methodology to exploit the synergy between SST and SSH measurements to provide enhanced 2D surface currents. Our approach combines the usage of advanced signal processing techniques, such as wavelet analysis, with dynamical approaches like the Surface Quasi-Geostrophic (SQG) equations.
ESA satellites (ERS-1/2 and Envisat) are an excellent source of opportunity to exploit the developed synergetic approach because they provide simultaneous measurements of SST and SSH measurements. These missions have been used to test the enhanced capabilities of our approach and the results obtained have been compared against independent SSH measurements provided by Jason-1/2 and CryoSat-2 platforms.
Furthermore, the pair of Sentinel-3 will follow their predecessors providing simultaneous SST and SSH measurements with the peculiarity that this mission will have a SARM altimeter on board. This altimeter has the potential to improve the resolution of across-track currents. Therefore, in preparation for the new Sentinels family, we have adapted our methodology to SARM characteristics and explored the capability to improve the estimation of surface 2D currents using SARM SSH measurements from CryoSat-2 and AVHRR measurements of SST.